Regulating transformer



Dec. 1, 1936 CH E 2,062,719

REGULATING TRANSFORMER Filed July 9, 1935 ll Sheets-Sheet 2 Fig: Z

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TRANSFORMER REGULATING Filed July 9, 1935 ll Sheets-Sheet ll Gear Le/Iscfiner, lnvenzor 3 flffomew scar REGULATING ll litilld i lllltltmlt Georg Leiscliner, Berlin-Schmockwita, Germany, assignor to N. I. M.@llil16ii&@lll6hl Apparateii liabrieken Meat, Utrecht, Netherlands Application .luly 9, 1935, Serial No. 3%,569 In Germany July 2c, 1934 it Claims.

The invention relates to regulator-transformers. Dne use of such transformers consists, for example, in maintaining the potential of an. alternating current net constant despite varyint loads or fluctuations in the feed potential. Another use is that of conversion of a constant auxiliaryv potential into a variable potential for supplying current to the motors of electric locomotives.

For the regulation of alternating fluxes, generally transformers are used in which one coil is provided with taps or leads which are com nected to contacts, so that different lengths ofthis coil can be connected in. In passing from one contact to the next, the electric current must ordinarily be interrupted for a short period of time. If such interruption is to be avoided, the connection must be established with the next succeeding contact before that with the preced ing one is broken, which then short-circuits the part of the coilbetween the two contacts. Power ful short-circuit currents are thereby produced in this part of the coil, which cause dangerous heat ing of the coil, and the interruption of which produces injurious arc The present invention relates to a regulating transformer in which these defects are avoided, by forming the ironcore of a plurality of partial cores or limbs and connecting the regulator coil with the tap contacts in such a manner that when two adjacent contacts and the coil section between them, are short-circuited the shorted portion of the circuit encompasses only one par tial core or limb, and the flux which would otherwise pass through this partial core or limbis forced off to the other partial cores or limbs.

Further advantages oi the invention will apyear more fully from the following description,

particularly when taken in conjunction with the I modification.

Fig. 3c is a diagrammatic side elevation a portion of the same.

iCi. Wi 119) Figs. e and 5 are diagrammatic views showing two possible arrangements of the primary and secondary coils on the partial cores.

Figs. 6, 7, and 8 are diagraatic plan views of further embodiments.

6c is a diagrammatic side elevation of the device shown in Fig. 6. i

Figs. 9 to 13 are diagrammatic views of an individual core section and the corresponding coils, at various stages during the movement of the movable contacts.

Fig. 14 shows diagrammatically several core sections and the electric connections between their coils.

Fig. 15 is a cross section of a device similar to that shown in Fig. 8.

Fig. 16- shows diagrammatically one type of ar= rangen'ient of the coils on a core section.

Fig. 17 is a cross section on the line [llll of Fig. 18 oi a further modification.

is is a cross section on the line i8-l oi Fig.

I the regulating transformer shown in Figs. 1 and la the iron core consists of two annular yokes m and the partial cores, or limbs. connecting these two yolres, said partial cores or limbs being designated a, Z"). The regulator coil 5 is passed lie-tween the partial cores so that it encompasses all the partial cores a, while the partial cores a lie outside the coil. These partial cores outside of the regulator coil are termed hereinafter magnetic flux; return conductors. that is, they" serve to complete a nagnetic circuit through the partial cores a and yo'ires m. The parts the regulator coil dorm the contacts of com tact group on i-Jnich slides a movable contact :0 table about the point i. (in passage or "f uisli 8 from a one contact to the .ere will he a shor" rcuiti'ng of that oi. {AME regulator coil Ii /lug hetween the two con tacts he movable contact 3 is wider than the space between contacts 2, so it will contact fore leaving the preceding is erran ernent' prevents any complete ego of he circuit during the switching cp= oration. The short circuit current flowing in this the some time the iiux passing through theremaining partial cores is correspondingly increased. The flux is thus, to a certain extent, forced oil to the other partial cores or limbs, and the short circuit current passing in the short'circuited part of the coil must then remain within the order of magnitude of the magnetizing current.

The transformer described may also be used as an auto-transformer, if the primary voltage m applied at the terminals 5 and 6 while the regulated voltage, or secondary current, is taken off between one of the contacts 5 and 5 and the axis 4 of the movable contact.

In addition to the regulator coil, there may be a separate primary coil, which may pass between the partial cores in the same manner as the regulator coil, if necessary with a larger number of windings; or single coils may be arranged on'the partial cores, each of which encompasses several either of the partial cores or of the magnetic re-- turn conductors, in which case the coils are preferably connected in parallel; or each primary cell may encompass only one partial core, the coils then being connected in series.

Figs. 2 and 2a show a regulating transformer similar in operation, but with a different type of iron core. This form embodies a plurality of par tial cores a, each consisting of two limbs a1. and on, each of which is magnetically closed by a magnetic flux return conductor In or bn. The individual limbs are, however, magnetically separated from one another. The regulator coil and contacts are arranged in the same manner as in Fig. 1.

In case the transformer is not to be used as an auto-transformer, but is to be provided with a primary coil separate from the regulator coil, this coil may be arranged as described for Fig. l; or it may consist of a plurality of coils connected in parallel, each encompassing two magnetic iiux return conductors in and Du associated with different partial cores.

Figs. 3 and 3a show a regulating transformer which is an improvement on that of 2. In order to subdivide the regulation stages with still greater precision, the regulator coil is pro with taps l which pass between the limbs an of each partial core the contacts 8 contact path or group. When two adiace tacts are short-circuited, only one limb tiai core is encom assed by the short circ rent, and the flux is forced from this otl'ier limbs magnetically connected there In order to facilitate this forcing off of the if" there may be disposed, between the limbs partial core, magnetically conducting connec tions, for example in the form of iron. wedges 5. These iron wedges are, however, not absolutely indispensable, and they may be omitted particularly when the primary coil consists of indiv 'ual coils connected in parallel, each of ta 'hich compasses the limbs or and an of a partial c Figs. 4. and 5 show the arrangement of the mary and secondary coils diagrammatically. cording to Fig. 4 each of the primary co which are connected in parallel, encompasse magnetic flux return conductors of limbs ciated with difierent partial cores. Upon the short-circuiting of two adjacent contacts the secondary coil by the movable contact, the flux in. the limb encompassed by the sl'lort-circuited coil is suppressed, whereby the flux in the limb or the adjacent core section the magnetic flux return conductor of which is encompassed by the same primary coil is correspondingly increased. This action on adjacent core sections, which is often undesirable, is avoided with the arrangement of primary coils shown in Fig. 8 and the following figures.

Fig. 5 shows a primary coil arrangement in whichthe limbs of a partial core as well as the return conductors of the limbs of different partial cores are encompassed by primary coils. The primary coils l0 which encompass the limbs or and on are connected together in parallel, as are also the coils 9 which encompass the return conductors b1 and 1311, and the two coil groups are connected together in series.

A still finer de ree of regulation may be obtained if taps are provided not only between the limbs but also between the return conductors.

Figs. 6 and 6a show an arrangement of this type. The iron core, as in the regulating transformer of Fig. 1, consists of two annular yokes m and the partial cores aand the return conductors b connecting them. Each. partial core consists of two limbs or and an; each return conductor of two limbs bx and bu. As in Fig. 3, the taps l are connected to the contacts 8 of a contact group; and in addition there are provided taps l I which pass through or between the limbs of the return conductors and are connected to the contacts [2 of a second contact group. The movable contacts 3 and i3 slide on these two contact groups. The leads to the two movable contacts 3 and I3 are connected with the ends of the winding of an inductive potential balancer N, at the centre of which. the regulated potential is taken off at IS.

A finer subdivision may also be obtained without the use of two contact groups, by subdividing each partial core, not merely into two, but into a larger number of limbs. Fig. '7 shows a regulating transformer diagrammatically in which each. partial core is subdivided into four limbs or, an, am, and dry; magnetic flux return conductors are associated therewith. Ii a partial core consists of n limbs, then (n-1) taps can be arranged on the part of the regulator coil which encompasses this partial core, and these taps must be connected to the contact group in such a manner that each two adjacent taps together with the part of the regulator coil between them encompass the o e on of one limb.

8 shows .g transformer the parti l cores of which are sch subdivided. into three s :11, an, and am, and their respective return rluctors. The individual windings l6 0! the primary coil each encompass three of the return conductors corresponding to the same partial core.

The operation of the regulating transformers is best explained by considering the transformer as consisting of a large number of individual ranslormers. These individual transformers are arranged in groups. Each limb ax, respectively an, etc, and the corresponding return conductors respectively t n, eta, together form the core of such an. individual transformer.- Each core section is preferably a group of at least two such individual transformers. The procedure in a core section of a regulating transformer consldered as such a group is explained with reference to Figs. $43.

The two limbs of the partial core are designated by a: and an, as in the preceding figures. particularly Fig. 3, the magnetic return conclusters by in and bu. Fig. 9 shows the regulator coil l without current and open. Only a. slight magnetizing current flows in primary coil 20. If contact 3 moves further in the direction off to the limb (11.

W s anemia at of the arrow the position shown in Fig. 10 is next attained. The stationary contacts l? and it are now bridgedby the movable contact The short circuit current in the part of the regulator coil encompassing the limb in is limited, as the flux generated by primary coil 23 is forced from the limb a: to the limb an. As a result the primary coil is traversed only by the magnetizing current necessary for generating the flux in the limb an, and the short circuited coil encompassing the limb or is traversed by a short circuit current corresponding to this primary current.

If contact 3 moves further the short circuit between contacts l1, I8 is broken, resulting in the case of Fig. 11. Injurious phenomena do not arise when the short circuit is broken, as only a negligibly small load is cut out.

In the position of Fig. 11, the part of the regulator coil encompassing the limb a: is traversed by operating current; the limb an in such a case would normally act to choke the primary current.

and, through the magnetic coupling of the two currents, the secondary current also. This un desirable action .is prevented by the fact that the limb an is highly supersaturated by the primary current. The limb a: now forms, to a certain degree, with the current-traversed part of the secondary coil and the primary coil, a normaltransformer, to which a choke formed by primary coil 20 and the limb an is connected in series on the primary side. This choke, being highly supersaturated only by the primary current, is practically almost inactive.

The undesired reaction on the secondary potential generated caused by this supersaturation is very slight in each core section or group. When use is made of a large number of core sections, it is insignificant with relation to the total potential generated, as it remains limited to the individual core sections.

If the regulating transformer consists of only a relatively small number of core sections or groups, or if more stringent requirements are placed on the potential generated, it is advantageous to provide each individual limb with an. air gap, so dimensioned that the flux generated by the operating current is small as compared with the flux generated by the primary coil.

If necessary, a condenser 24 (Fig. 14) can be advantageously connected across the leads of the secondary circuit in order to prevent damage by vibrations of the potential arising as a result of the supersaturation, and a resistance 25 (Fig. 14) may be similarly arranged in order to suppress the occurrence oscillations.

On further movement of contact 3, contacts l8 and I9 are conductively connected as shown in Fig. 12. In this case the conditions are much the same as in the case of Fig. 10. The coil section encompassing the limb an is short-circuited, but the short circuit current is limited because the flux generated by the primary coil is forced On breaking the short circuit, therefore, there is in this case also only a small load to be cut out, and injurious phenomena do not arise.

Fig. 13 shows the final position. The entire winding of the secondary coil is traversed by the operating current. Connected with contact i9 is the first contact of the next, similar, core section, so that the same procedure is repeated on furthermovement of contact 3 in the same direction.

Fig. 14 shows diagrammatically an arrangement comprising a plurality of such groups or core sections, similar to that of Figs. 9 to i3,

which can also be arranged differently from the annular. arrangement shown in Figs. 1 to 8, that is, side by side in a row or line.

In order to avoid the necessity of forming the transformer of a large number of core sections or groups of individual transformers, it is preferable to have the secondary coil pass several times through the whole series of core sections or through each individual core section. In the embodiment of Fig. ll, several parallel contact paths, successively traversed by movable contacts, would be necessary in the first case. It is therefore generally preferable to dispose the partial poles annularly, as described.

The regulator coil may then, as shown in Fig. 15, be passed spirally through the annularly arranged partial cores and the contact groups likewise arranged helically at the interior of the annulus. which corresponds to that of the windings, serves for guiding the movable contact. The movable contact may also be provided with suitable parts, such as lugs, so as to be automatically guided by the helical contact groups.

The primary coil is not, in general, formed as shown in the diagrammatic figures of only. one, but instead of a larger number of windings. The secondary coil may consist in practice of a single wire or loop. With the secondary coil also, however, each individual limb may be en compassed by a large number of windings. These coils must then be so connected with each other and with the contacts of the contact groups as to fulfill the fundamental requirement, that when two adjacent contacts are-short-circuited the short-circuited part of the regulator coil encompasses only one limb or only a part of the cross section of. a partial core.

Fig. 16 shows diagrammatically the arrangement of the primary and secondary coils in the cases just described.

Figs. 17 and 18 show a further type of regulating transformer. Fig. 18 is a section so drawn that the left half shows the primary coil, while the right half shows the uppermost winding of the regulator coil, the contact group and the movable contact being shown in plan view for greater clearness. As shown on the figures the core sections may be disposed close together, so that the entire apparatus occupies but little space.

In the regulating transformer shown, the iron core consists of six core sections, A, B, C, D, E, F, each of which consists of a partial core, each partial core consisting of two limbs or, an and return conductors in and 221:. Each limb is connected by yokes m with its corresponding return conductor. The core is laminated, that is formed of iron plates which are perpendicular to the plane of Fig. 18. In' this form, the portions of the regulator, coil within the iron core sections extend radially of the annulus, while the portions outside the core sections extend peripherally thereof. The regulator coil 5| begins at 52 and first passes in a radial direction between limb an and its return conductor bn of core section A to the interior of the annulus and there connected with the first contact Bl of the contact group. It then passes peripherally to the next core section, and then radially outward between limb or and its return conductor in of core section B, and then inwardly between limb an and its return conductor bn of core section B. A tap 53 passes between the limbs a1 and A threaded spindle the pitch of an to the second contact 62 of the contact path. In corresponding manner the regulator coil extends in a zig-zag path through all the core sections, to the tap connected with contact 12. At 54 the regulator coil bends obliquely downward out of the plane of the previously described windings in order, as shown in Fig. 1'7, to pass around the core a second and a third time in lower planes.

The primary coil consists of six individual coils, whichare connected in parallel. Each of these coils encompasses one partial core, that is the limbs er and an of one of the six core sections. In the regulating transformer shown each of these coils consists of two vertically spaced partial coils 55 and 56, connected in series.

For taking off the current use is made of the brush 66, which is pressed by a spring 51 against the stationary contacts 8|, 62, 63, and so on. The brush, during rotation, is raised and lowered by the screw spindle 58 in accordance with the pitch of the contact group. The brush is rotated in any manner, for example, by means of the hand wheel 13 which is mounted on the rotatable part '14, in which shaft 58 of the contact carrying device is slidable. The shaft is carried along to follow the rotation of part 14 by means of a guide key 15 which engages in a groove or slot 16 in the shaft. In the position shown in Fig. 18, the brush connects contacts 66 and 51. The short circuit formed thereby encompasses the limb an of core section D. Since the corre sponding primary coil encompasses the two limbs or and an of core section D, the flux in the limb an will be suppressed, whereby the flux in the limb a1 is correspondingly increased. The load to be out out when this short circuit is broken,

' on further rotation of the brush, is so slight that sparks or arcs practically do not occur.

Instead of arranging the regulator coil as described, to traverse the core sections radially, an arrangement may also be used in which the regulator coil traverses the core sections in a direction parallel with the axis of the annulus. Figs. 19 and 20 show such an arrangement.

In the regulating transformer of Figs. 19 and 20 the limbs of each partial core are united in one piece, while the return conductors are separated. As in the arrangement of Figs. 17 and 18, the regulating transformer comprises six core sections, 0, P, Q, R, S, T, each consisting of a partial core or limb a, two return conductors bi and bn, which together have the same iron cross section as the partial core a, and two yokes m connecting the partial core and return conductors. The primary windings are indicated generally at 9|.

The regulator coil 8| begins at 82. In this modification, the portions of the regulator coil within the core extend parallel to the axis of the annulus, while the portions outside the core extend peripherally thereof. It first passes between partial core a and return conductor in of core section 0 downwardly, in a. direction parallel to the axis of the annulus, then peripherally to the opposite side of partial core a and again upwardly between partial core 0; and return conductor bu, and thuswinds four times about partial core a. Each of such windings is provided at the top and bottom with a tap 83, 84, 85, 86, 81, 88, 89, 90, respectively, these taps being connected to a collector-like contact group. As shown in Fig. 19, each alternate plate 94 of this contact group extends upwardly, and each intermediate plate 93 downwardly, and such plates connect each with the top and bottom taps respectively.

Each partial core a is also encompassed by a primary coil. The six primary coils are connected in parallel. The arrangement of the coils requires that, in contrast to the previously described arrangements, the plates of the laminated iron core must lie parallel with the plane of Fi 20.

The brush 92 serves for taking ofi. current. If this brush conductively connects two adjacent contact plates, such as 93 and 94 (Fig. 20), the short circuit comprising the taps 86 and 81 and the intermediate part 95 of the regulator coil will encompass only half the cross section of partial core a of core section 0, as it encompasses only the magnetic flux circuit through the return conductor bn. The flux generated by the primary coil in partial core a is forced from return conductor bu to return conductor b1, so that in this construction also the short circuit current is so small as to prevent injurious phenomena from arising.

It is, of course, understood that in all the arrangements described the direction of the energy may be reversed, and the regulator coils may be connected as primary coils to the source of supply, and the fixed coils as secondary coils to the point of consumption.

I wish it to be understood that I do not de sire to be limited to the exact details of the construction shown and described, for obvious modifications will occur to a person skilled in the art.

I claim:

1. Regulating transformer, comprising an iron core, a regulator coil and a group of contacts, said iron core comprising a plurality of partial cores, said regulator coil being so connected with the contacts that when two adjacent contacts are short-circuited the short circuit encompasses only one partial core.

2. Regulating transformer, comprising an iron core, a regulator coil and a group of contacts,

said iron core comprising a plurality of annularly disposed partial cores, said regulator coil being so connected with the contacts that when two adjacent contacts are short-circuited the short circuit encompasses only one partial core.

3. A regulating transformer, comprising an iron core, a regulator coil and a group of contacts, said iron core consisting of a plurality of annularly disposed partial cores and magnetic flux return conductors associated therewith, the regulator coil passing in a zig-zag path between the partial cores and the return conductors, and being so connected with the contacts that upon short-oircuiting of two adjacent contacts the short circuit encompasses only one partial core.

4. A regulating transformer, comprising an iron core, a regulator coil and a group, of contacts, said iron core consisting of a plurality of annularly disposed partial cores and magnetic flux return conductors associated therewith, the regulator coil passing in a zig-zag path between the partial cores and the return conductors, parts of the regulator coil forming the said contacts and being so arranged that upon short-circuiting of two adjacent contacts the short circuit encompasses only one partial core.

5. Regulating transformer, comprising an iron core, a regulator coil and a. group of contacts, said ironcore comprising a plurality of partial cores, each partial core consisting of a plurality of limbs, said regulator coil being so connected accentewith the contacts that when two adjacent contacts are short-circuitecl the short circuit e compasses at most the limbs of one partial core.

6. Regulating transformer, comprising an iron core, a regulator coil, taps connected to the regulator coil and to a group of contacts, said iron core comprising a plurality of partial cores, the taps being so connected to the contacts that upon short-circuiting of two adjacent contacts the short circuit encompasses only one partial core.

7. Regulating transformer, comprising an iron core, a regulator coil, taps connected to the regulator coil and to a group of contacts, said iron core consisting of a plurality of annularly arranged partial cores and magnetic flux return conductors associated therewith, each partial core consisting of a plurality of limbs, the regulator coil passing in a zig-zag path between the partial cores and the return conductors, the taps being so connected to the contacts that upon short-circuiting of two adjacent contacts the short circuit encompasses only one limb.

8. Regulating transformer, comprising an iron core, a regulator coil, taps connected to the regulator coil, a group of. contacts, said taps being connected to some of said contacts, said iron core consisting of a plurality of annularly arranged partial cores and magnetic fins return conductors associated therewith, each partial core con= sisting of a plurality of limbs, the regulator coil passing in a zig-zag path between the partial cores and the return conductors, parts of the regulator coll forming the remainder of the contacts of thecontact group, the taps being so passed between the limbs of the partial cores that upon short clrcuiting of two adjacent contacts the short circuit encompasses only one limb.

9. Regulating transformer, comprising an iron core, a primary coil, a regulator coil and agroup of contacts, said iron core comprising a plurality of partial cores the primary coil consisting of a plurality of coils each of which encompasses a plurality of partial cores, said regulator coil being so connected with the contacts that when two adjacent contacts are short-circuited the short circuit encompasses only one partial core.

10. Regulating transformer, comprising an iron core, a primary coil, a regulator coil and a group of contacts, said iron core comprising a. plurality of partial cores, the primary coil consisting of a plurality of coils connected in parallel, said regulator coil being so connected with the contacts that when two adjacent contacts are short-circuited the short circuit encompasses only one partial core.

11. Regulating transformer, comprising an iron core, a primary coil, a regulator coil and a group of contacts, said iron core comprising plurality of partial cores, each partial core consisting of a plurality of limbs, a magnetic flux return con ductor associated with each limb, the primary coil consisting of a plurality of coils connected in parallel, each of which encompasses a plurality of limbs, the regulator coil being so connected with the contacts that upon short-circuiting of two adjacent contacts the short circuit encompasses only one limb.

12. Regulating transformer, comprising an iron core, a primary coil, a regulator coil and a group of contacts, said iron core comprising a plurality of annularly disposed partial cores, each partial core consisting of a plurality of limbs, a magnetic flux return conductor associated with each limb, the primary coil consisting of a plurality of coils connected in parallel, each of which encompasses a plurality of limbs, the regulator coil being so connected with the contacts that upon shortcircuiting of two adjacent contacts the short circuit encompasses only one limb.

l3. Regulating transformer, comprising an iron core, a primary cell, a regulator coil, taps connected to the regulator coil and to a group of contacts, said iron core comprising a plurality oi partial cores, each partial core consisting of a plurality of limbs, a magnetic flux return conductor associated with each limb, the primary coil consisting of a plurality of coils connected in parallel, each of which encompasses a plurality of limbs, the taps being so connected to the contacts that upon short-circuiting of two adjacent contacts the short circuit encompasses only one limb.

14. Regulating transformer, comprising an iron core, a primary coil, a regulator coil, taps connected to the regulator coil and to a group of com tacts', said iron core comprising a plurality of annularly disposed partial cores each partial core consisting of a plurality of limbs, a magnetic flux return conductor associated with each limb, said return conductors being disposed between the partial cores, the primary coil consisting or" a plurality of coils connected in parallel, each 'encompassing a plurality of limbs, the regulator coil passing in a zig-zag path between the partial cores and the return conductors, the taps being so connected to the contacts that upon shortcircuiting of two adjacent contacts the short circuit encompasses only one limb.

15. Regulating transformer, comprising an iron core, a primary coil, a regulator coil, taps connected to the regulator coil and to a group of con-= tacts, said iron core comprising a plurality of annularly disposed partial cores, each partial core consisting of a plurality of limbs, a magnetic flux return conductor associated with each limb, said return conductors being disposed between the partial cores, the primary coil consisting of a plurality of coils connected in parallel, each errcompassing the limbs of one partial core, the

regulator coil passing in a zig-zag path between the partial coresand the return conductors, the taps being so connected to the contacts that upon short-circuiting of two adjacent contacts the short circuit encompasses only one limb.

l6. Regulating transformer, comprising an iron core, a primary coil, a regulator coil, taps connected to the regulator coil and to a group of contacts, said iron core consisting of a plurality of annularly disposed core sections of laminated iron having the laminations perpendicular to the plane of the annulus, each core section consisting of a partial core and magnetic flux return conductors each partial core consisting of a plurality of limbs, each magnetic flux return conductor associated with a limb, said return conductorsbeing disposed between the partial cores, the primary coil consisting of a plurality of coils connected in parallel, each encompassing the' l7. Regulating transformer, comprising an iron core, a primary cofl, a regulator coil, taps connected to the regulator coil and to a group of contacts, said iron core consisting of a plurality of annularly disposed core sections of laminated iron having the laminations parallel to the plane of the annulus, each core section consisting of a partial core and magnetic flux return conductors associated with the partial core, said return conductors being disposed between the partial cores, the primary coil consisting of a plurality of coils connected in parallel, each encompassing a par- 

